JP2005331449A - Angular velocity sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular velocity sensor improved in reliability by reducing the error of the angular velocity caused by the acceleration of an oscillator to its moving direction. <P>SOLUTION: An oscillator 22 of a tuning fork type is provided with a shaft part 28 having a pair of arms 30 formed of a piezoelectric element. A main body 26 constituted of IC 27 for controlling the oscillator 22 and for detecting the angular velocity, a substrate 32 for mounting the IC 27 and for supporting the oscillator 22, and a first correction circuit 35 for correcting the Coriolis force caused by imbalance of mass of a pair of arms 30 if the acceleration is generated in a moving direction of the oscillator 22, and the case 34 for storing the IC 27, substrate 32, and the first correction circuit 35. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an angular velocity sensor used for various mobile devices.

  Hereinafter, a conventional angular velocity sensor will be described with reference to the drawings.

  FIG. 8 is an attachment state diagram showing a state in which a conventional angular velocity sensor is attached to a vehicle, FIG. 9 is a perspective view when the angular velocity sensor is used, and FIG. 10 is an oblique angle of the vibrator with respect to the moving direction of the vibrator. It is side surface sectional drawing of the same angular velocity sensor which is.

  8 and 9, the conventional angular velocity sensor includes a vibrator 2 for detecting angular velocity, and a main body 6 on which the vibrator 2 is mounted and attached to a mobile device 4 such as a car.

  The vibrator 2 has a tuning fork shape in which a pair of arm portions 10 are connected to a shaft portion 8 and is composed of a piezoelectric element. The main body 6 controls the vibrator 2 and detects an angular velocity, and this IC. And a substrate 12 that supports the vibrator 2 and a case 14 that houses the IC and the substrate.

  In use, the vibrator 2 is tilted in the direction opposite to the tilting direction of the vibrator 2 with respect to the moving direction of the vibrator 2 accompanying the movement of the mobile device 4 and mounted on the main body 6. The inclination angle of the vibrator 2 with respect to the direction is set to a substantially right angle.

  Then, as shown in FIG. 10, the vibrator 2 is driven in a direction perpendicular to the moving direction of the vibrator 2 to generate a Coriolis force in the same direction as the moving direction of the vibrator 2.

For example, Patent Document 1 is known as prior art document information related to the invention of this application.
JP 2003-227844 A

  In the above configuration, since the vibrator 2 is mounted on the main body 6 so that the inclination angle of the vibrator 2 with respect to the moving direction of the vibrator 2 is substantially perpendicular, the vibrator 2 is moved relative to the moving direction of the vibrator 2. There is little error in angular velocity due to tilting.

  However, if the mobile device 4 is a car or the like as in the above configuration, there is a problem in that an error occurs in the angular velocity due to acceleration in the moving direction of the vibrator 2 when starting or decelerating. It was. In particular, since the vibrator 2 has a tuning fork type shape having a pair of arm portions 10 on the shaft portion 8, as shown in FIG. 9, if mass unbalance occurs in the pair of arm portions 10, the moving body One of the arm portions 10 bends larger than the other arm portion 10 with respect to the direction in which the acceleration of the device 4 occurs, and it is erroneously detected that an angular velocity has occurred due to the difference in the amount of bending, and an error in angular velocity is detected. Has occurred.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to provide an angular velocity sensor in which an error in an output signal as an angular velocity caused by acceleration in a moving direction of a vibrator is reduced and reliability is improved.

  In order to achieve the above object, the present invention has the following configuration.

  In particular, the present invention is configured to include a first correction circuit that corrects an error in Coriolis force caused by mass unbalance between a pair of arm portions when acceleration occurs in the moving direction of the vibrator. .

  According to the present invention, since the first correction circuit for correcting the error of the Coriolis force caused by the mass unbalance of the pair of arm portions is provided, acceleration occurs in the moving direction of the vibrator, and the pair of arms Even if an error occurs in the Coriolis force due to the mass imbalance of the portion, the error in the Coriolis force can be corrected by the first correction circuit.

  As a result, it is possible to reduce the angular velocity error caused by the acceleration in the moving direction of the vibrator and improve the reliability.

  Hereinafter, an embodiment of the present invention will be described.

  1 is a perspective view of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is an attachment state diagram showing a state in which the angular velocity sensor is attached to a vehicle, and FIG. 3 is a first correction circuit used in the angular velocity sensor. 4 is an enlarged view of part A of FIG. 2, and is a side sectional view of the angular velocity sensor in which the tilt angle of the vibrator with respect to the moving direction of the vibrator is an acute angle. FIG. FIG. 6 is an enlarged view of a cross-sectional side view of the angular velocity sensor in which the tilt angle of the vibrator is perpendicular to the moving direction of the vibrator, and FIG. 6 is an enlarged view of a portion A in FIG. It is side surface sectional drawing of the angular velocity sensor from which bending amount differs.

  1 and 2, an angular velocity sensor according to an embodiment of the present invention includes a vibrator 22 for detecting angular velocity, and a main body 26 on which the vibrator 22 is mounted and attached to a moving body device 24 such as a car. ing.

  The vibrator 22 has a tuning fork shape having a pair of arm portions 30 on a shaft portion 28, and is composed of a piezoelectric element.

  The main body 26 controls the vibrator 22 and detects an angular velocity, an IC 27 that mounts the IC 27 and supports the vibrator 22, and when acceleration occurs in the moving direction of the vibrator 22, It has a correction circuit 35 that corrects an error in the Coriolis force caused by the mass unbalance of the arm unit 30, and a case 34 that houses the IC 27, the substrate 32, and the first correction circuit 35. The first correction circuit 35 is shown in FIG. 3, and includes a drive terminal 21 for driving the vibrator 22, a monitor terminal 23 for monitoring the drive state of the vibrator 22, and a Coriolis force. A sensing terminal 25 for detecting the occurrence state of the angular velocity and an output terminal 29 for outputting the occurrence state of the angular velocity as a signal.

  In addition, when the angular velocity sensor is used, as shown in FIG. 4, the vibrator 22 tilts (tilt angle (α)) with respect to the moving direction of the vibrator 22 accompanying the movement of the mobile device 24. As shown in FIG. 5, the vibrator 22 is mounted on the main body 26 in advance by tilting (tilt angle (β)) in the direction opposite to the tilt direction of the vibrator 22, and the vibration in the moving direction of the vibrator 22. The inclination angle of the child 22 is set to be a substantially right angle.

  Then, the vibrator 22 is driven in a direction perpendicular to the moving direction of the vibrator 22 to generate a Coriolis force in the same direction as the moving direction of the vibrator 22.

  At this time, the vibrator 22 has a tuning fork shape having a pair of arm portions 30 on the shaft portion 28. Therefore, if mass imbalance occurs in the pair of arm portions 30, as shown in FIG. When acceleration occurs in the traveling direction of the mobile device 24, either one of the arm portions 30 bends more than the other arm portion 30, and it is erroneously detected that an angular velocity has occurred due to the difference in the amount of bending. An error occurs in the output signal. An error in angular velocity generated due to the mass imbalance of the pair of arm portions 30, that is, an error in Coriolis force is corrected by the first correction circuit 35.

  The first correction circuit 35 may correct by detecting the mass imbalance of the pair of arm portions 30 and correcting the detected amount.

  With the above configuration, the first correction circuit 35 that corrects the error of the Coriolis force generated due to the mass imbalance of the pair of arm portions 30 is provided. Even if an error occurs in the Coriolis force due to the mass unbalance of the arm portion 30, the first correction circuit 35 can correct the error in the Coriolis force and improve the reliability.

  In the embodiment of the present invention, since the tilt angle of the vibrator 22 with respect to the moving direction of the vibrator 22 is set to be substantially a right angle, an error in angular velocity due to the tilt of the vibrator 22 is suppressed. However, the inclination angle (inclination angle (α)) of the vibrator 22 with respect to the moving direction of the vibrator 22 and the mounting angle (inclination angle (β)) for mounting the vibrator 22 on the main body can be completely matched. If the angular velocity error due to the tilt of the vibrator 22 is not possible, the second correction for angle difference correction that corrects the error due to the angle difference between the tilt angle (α) and the tilt angle (β). If the circuit 37 is provided, an error in angular velocity can be reduced. As the second correction circuit 37, there is the one shown in FIG. 7, and in the same way as the first correction circuit, a drive terminal 21 for driving the vibrator 22 and a driving state of the vibrator 22 are monitored. Monitoring terminal 23, sensing terminal 25 for detecting the Coriolis force generation state, and output terminal 29 for outputting the angular velocity generation state as a signal.

  Furthermore, if the second correction circuit 37 for correcting the angle difference is provided with a detection circuit that automatically detects the angle difference, the error due to the angle difference is corrected in real time, and the error of the angular velocity is accurately reduced. can do.

  As described above, the angular velocity sensor according to the present invention can reduce the error of the angular velocity caused by the acceleration in the moving direction of the vibrator and improve the reliability, and thus can be applied to various mobile devices.

The perspective view of the angular velocity sensor in one embodiment of this invention Mounting state diagram showing the same angular velocity sensor mounted on the car Circuit diagram of a first correction circuit used in the angular velocity sensor FIG. 3 is an enlarged view of a part A in FIG. 2, and is a side cross-sectional view of the angular velocity sensor in which the tilt angle of the vibrator with respect to the moving direction of the vibrator is an acute angle. FIG. 3 is an enlarged view of a part A in FIG. 2, and is a side cross-sectional view of the angular velocity sensor in which the inclination angle of the vibrator is perpendicular to the moving direction of the vibrator. FIG. 3 is an enlarged view of a portion A in FIG. 2, and is a side cross-sectional view of an angular velocity sensor in which the bending amount of the arm portion of the vibrator differs Circuit diagram of second correction circuit used in same angular velocity sensor A mounting state diagram showing a state in which a conventional angular velocity sensor is mounted on a car Perspective perspective view when using the same angular velocity sensor Side sectional view of the same angular velocity sensor in which the tilt angle of the vibrator is substantially perpendicular to the moving direction of the vibrator

Explanation of symbols

21 Terminal for Drive 22 Vibrator 23 Terminal for Monitor 24 Mobile Device 25 Terminal for Sensing 26 Main Body 27 IC
28 Shaft portion 29 Output terminal 30 Arm portion 32 Substrate 34 Case 35 First correction circuit 37 Second correction circuit

Claims (3)

The vibration associated with movement of the mobile body device, comprising: a shaft portion; an angular velocity detecting vibrator having a pair of arm portions connected to the shaft portion; and a main body mounted with the vibrator and attached to the mobile body device. When the vibrator tilts with respect to the moving direction of the child, the vibrator is tilted in the direction opposite to the tilting direction of the vibrator and mounted on the main body, and the vibration with respect to the moving direction of the vibrator The tilt angle of the child is substantially right angle, the vibrator is driven in a direction perpendicular to the moving direction of the vibrator, and Coriolis force is generated in the same direction as the moving direction of the vibrator. The angular velocity sensor according to claim 1, further comprising a first correction circuit that corrects an error in Coriolis force caused by mass imbalance between the pair of arm portions when acceleration occurs in the movement direction. The angular velocity according to claim 1, further comprising a second correction circuit that corrects an error caused by an angle difference between an inclination angle of the vibrator with respect to a moving direction of the vibrator and a mounting angle at which the vibrator is mounted on the main body. Sensor. The angular velocity sensor according to claim 2, wherein the correction circuit is provided with a detection circuit that automatically detects an angle difference.

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